IC modules mounting IC chips and having functions of contact communication and contactless communication provide communication modes according to users' various applications. Specifically, such an IC module is mounted to a card body that is capable of power supply and communication by being electromagnetically coupled with the IC module, for use as a dual IC card. Electrical connection between the IC module and the card body by electromagnetic coupling can minimize destabilization of electrical connection between the IC module and the card body. This is because if the IC module and the card body are directly connected by a conductive connecting member, such as solder, the connecting member may be broken when the dual IC card is bent.
As such a dual IC card in which the IC module and the card body are electrically connected by electromagnetic coupling are described, for example, in PTLs 1 through 3.
An IC module for such a dual IC card has a surface on which a terminal used for an interface (contact terminal portion) is formed for contact with an external contact machine, and a rear surface on which a connecting coil is formed for transformer coupling (electromagnetic coupling). The IC module has a base which is subjected to a through-hole plating process to form a bridge (bridge wiring) on the surface of the base, so that the outermost end of the connecting coil is moved to the center of the base. Such a through-hole plating process herein refers to forming a through hole in the base by punching or the like and forming wiring in the through hole by plating or the like.
The terminal on the surface of the base and the IC chip on the rear surface are connected by hole-punching wire bonding, which is a known wire bonding process using a wire inserted through a through hole of a base.
Contact communication dual IC cards are used for applications that need reliability and security, such as large quantities of data exchange by credit-card transactions or communication for account settlement procedures. In contrast, contactless communication dual IC cards are used for applications where communication data volume is small and main communication is authentication, such as gate control for allowing someone to enter or leave a room.